Chinese Manufacturing Performance from Multilateral Perspective: 1980-2004

Based on our research work of 1998, we discuss Chinese manufacturing performance from multilateral perspective in 1980-2004 through performing the comparison of labour productivity between China and its trade partners so as to better understand the problems of RMB exchange rate. We talk about Chinese manufacturing competitiveness through the multilateral comparison of PPPs, relative price levels, labor productivity and ULCs, with the PPPs being standardized according to the base year 1997. All of the results are compared with those in the year 1987. The following findings are presented: in Chinese manufacturing, the various PPPs in the base year 1997 are approximately 3.7 yuan/international $. After the middle 1980s, the relative price turns the lowest in all the five investigation countries. Furthermore, it is still trending downward. ULC is declining albeit the fluctuations. In the 1980s, there is no "catch-up" rapid growth in labor productivity. However, after 1992, it has shown a distinct "catch-up", though with the low level.Multilateral comparison, Manufacturing, International competitiveness

First-order multivariate integer-valued autoregressive model with multivariate mixture distributions

The univariate integer-valued time series has been extensively studied, but literature on multivariate integer-valued time series models is quite limited and the complex correlation structure among the multivariate integer-valued time series is barely discussed. In this study, we proposed a first-order multivariate integer-valued autoregressive model to characterize the correlation among multivariate integer-valued time series with higher flexibility. Under the general conditions, we established the stationarity and ergodicity of the proposed model. With the proposed method, we discussed the models with multivariate Poisson-lognormal distribution and multivariate geometric-logitnormal distribution and the corresponding properties. The estimation method based on EM algorithm was developed for the model parameters and extensive simulation studies were performed to evaluate the effectiveness of proposed estimation method. Finally, a real crime data was analyzed to demonstrate the advantage of the proposed model with comparison to the other models

Social Turing Tests: Crowdsourcing Sybil Detection

As popular tools for spreading spam and malware, Sybils (or fake accounts) pose a serious threat to online communities such as Online Social Networks (OSNs). Today, sophisticated attackers are creating realistic Sybils that effectively befriend legitimate users, rendering most automated Sybil detection techniques ineffective. In this paper, we explore the feasibility of a crowdsourced Sybil detection system for OSNs. We conduct a large user study on the ability of humans to detect today's Sybil accounts, using a large corpus of ground-truth Sybil accounts from the Facebook and Renren networks. We analyze detection accuracy by both "experts" and "turkers" under a variety of conditions, and find that while turkers vary significantly in their effectiveness, experts consistently produce near-optimal results. We use these results to drive the design of a multi-tier crowdsourcing Sybil detection system. Using our user study data, we show that this system is scalable, and can be highly effective either as a standalone system or as a complementary technique to current tools